JPH06271708A - Polychloroprene rubber composition and wire and cable coated therewith - Google Patents

Abstract

PURPOSE:To obtain the subject composition improved in electrical insulation properties, mechanical strengths, extrudability and scorching resistance by mixing a polychloroprene rubber, with a fine silicone resin powder, carbon black and a vulcanizing agent. CONSTITUTION:This rubber composition is obtained by mixing a composition prepared by mixing 100 pts.wt. polychloroprene rubber with 5-50 pts.wt. fine silicone resin powder of a mean particle diameter of 0.5-100mum and 10-50 pts.wt. carbon black of a mean particle diameter of 85mum or below with a specified amount of a vulcanizing agent and optionally a vulcanization accelerator. A cable core 4 formed by twisting the desired number of insulated core wires 3, 3 is extrusion-coated with this composition to obtain an electric wire or cable having a sheath 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polychloroprene rubber composition having both mechanical properties and electrical insulation properties, and an electric wire / cable coated with a vulcanized product of this rubber composition.

[0002]

2. Description of the Related Art Polychloroprene rubber is a rubber having excellent oil resistance and chemical resistance. For example, in the field of electric wires and cables, electric cables required to have oil resistance and chemical resistance, for example, captyre cable, etc. It is widely used as a sheath material. This cabtire cable is mainly used as a power feeding cable at a temporary construction site of a building or the like, but at such a construction site, its handling is rough, so that the cable is easily damaged. Therefore, the polychloroprene rubber composition used as a sheath material for a captyre cable is required to have improved mechanical strength. Further, in recent years, a sheath material for a captyre cable is also required to have excellent electrical insulation properties from the viewpoint of preventing electric leakage accidents. In response to such a demand, conventionally, polychloroprene rubber has been blended with various reinforcing materials, additives and the like to improve its mechanical properties. Among them, the compounding of carbon black with polychloroprene rubber is regarded as a general-purpose technique because it has the largest reinforcing effect.

[0003]

However, when a large amount of carbon black is added to the polychloroprene rubber in anticipation of its excellent reinforcing effect, the scorch resistance and electric insulation of the resulting rubber composition are deteriorated. On the other hand, when the compounding amount of carbon black is reduced, the electrical insulating property of the rubber composition obtained can be maintained in an allowable range, but the mechanical strength becomes insufficient and the molded product is deformed during extrusion molding of the rubber composition. As a result, the shape retention of the extruded product deteriorates. The above problems are contradictory issues regarding the amount of carbon black compounded, and the conflicting issues have been solved, that is, a polychloroprene rubber composition having both excellent electrical insulation and mechanical strength has not yet been developed. Not not.

As a result of intensive investigations focusing on the above problems, the present invention is excellent in both electric insulation and mechanical strength, has good extrusion moldability, and is excellent in shape retention during extrusion molding. A polychloroprene rubber composition having good scorch resistance can be developed, and by applying this polychloroprene rubber composition to a coating material, an electric wire / cable having excellent characteristics can be developed. .

[0005]

[Means for Solving the Problems] That is, claim 1 of the present invention.
The polychloroprene rubber composition of 5 to 50 parts by weight of silicone fine powder having an average particle size of 0.5 μm to 100 μm and an average particle size of 85 nm are added to 100 parts by weight of the polychloroprene rubber.
The following carbon black is blended in a proportion of 10 to 50 parts by weight, and a desired amount of a vulcanizing agent is blended in the blended carbon black. Further, the electric wire / cable of the invention of claim 2 is characterized in that the vulcanized product of the polychloroprene rubber composition of claim 1 is coated on an electric conductor directly or through another coating material layer. Is.

The electric wires and cables referred to in the present invention are
An electric conductor 1 as shown in FIG. 3 is directly coated with the polychloroprene rubber composition of the present invention by extrusion coating, and this is heated and vulcanized to provide an insulated wire provided with an electric insulator layer 2, or as shown in FIG. Cable core 4 in which three insulated cores 3 and 3 are twisted together
A solid type electric cable (including a so-called captyre cable) having the sheath layer 6 formed by extrusion coating the polychloroprene rubber composition of the present invention thereon, or an insulating wire core 3 of a desired book as shown in FIG. 3 is a jacket type electric cable in which a sheath layer 6 is provided by extrusion coating the polychloroprene rubber composition of the present invention on a cable core 4 in which 3 is twisted together with inclusions 5.

As the polychloroprene rubber used in the present invention, those commercially available in general can be used. Examples of commercially available products include Neoprene TW (trade name, manufactured by Showa Denko KK, DuPont), Skyprene E-33 (trade name, manufactured by Tosoh Corporation).
and so on. Further, the fine powder of the silicone resin used in the present invention is added in order to impart abrasion resistance to the polychloroprene rubber, and its average particle size is 0.5-10.
Those having a size of 0 μm are used, but those having a range of 3 to 20 μm are particularly preferable. Something like this
It is sold by Toray Dow Corning Silicone Co., Ltd. under the trade names Trefill R-900 and E-500. If the amount of the fine powder of the silicone resin is less than 5 parts by weight based on 100 parts by weight of the polychloroprene rubber, the abrasion resistance of the rubber composition obtained cannot be sufficiently improved. Also, 50
When a large amount of the rubber composition is blended in excess of parts by weight, the rubber composition obtained will have poor tensile strength and elongation properties. Therefore, the blending amount of the fine powder of the silicone resin is preferably set within the range of 5 to 50 parts by weight, and the more preferable blending amount range is within the range of 10 to 40 parts by weight.

Carbon black having an average particle size of 85 nm or less is used as the carbon black used in the present invention, and as a commercially available product, the trade name is Diablack SH (manufactured by Mitsubishi Kasei Co., Ltd .: average particle size 22 to 30 nm). , Product name Asahi # 55
(Manufactured by Asahi Carbon Co., Ltd .: average particle size 49 to 84 nm). When the compounding amount of this carbon black is less than 10 parts by weight with respect to 100 parts by weight of the polychloroprene rubber, the mechanical strength of the obtained rubber composition is not improved. If the rubber composition is blended in a large amount in excess of 50 parts by weight, the electric insulation of the rubber composition will be deteriorated. For this reason, carbon black is preferably blended in the range of 10 to 50 parts by weight. As the vulcanizing agent, various known ones such as zinc oxide, magnesium oxide and lead oxide can be used. You may use these individually or in combination of 2 or more types. Among these, the combined use of zinc oxide and magnesium oxide is preferable in that a molded product having high strength can be obtained.

In addition to the above components, the polychloroprene rubber composition of the present invention may optionally contain a vulcanization accelerator, such as Accel # 22 (trade name, manufactured by Kawaguchi Chemical Co., Ltd .: ethylene thiourea). Name Nocceller TT (manufactured by Ouchi Shinko Co., Ltd .: Tetramethylthiuram disulfide), anti-aging agent, for example, Nocrac NBC (manufactured by Ouchi Shinko Co., Ltd .: nickel dibutyldithiocarbamate), softener, for example, trade name Kenflex A (Kenrich Chemical Co .: Alkylnaphthalene resin) and filler,
For example, it is possible to add Doxy clay (trade name: hard clay, manufactured by Vanderbilt Co., USA), talc, calcium carbonate and the like.

[0010]

In the polychloroprene rubber composition of the present invention, since an appropriate amount of fine powder of silicone resin is used together with carbon black, it has excellent electrical insulation and various mechanical properties. Become. Further, the electric wire / cable obtained by extrusion coating the polychloroprene rubber composition of the present invention has both excellent electrical insulation properties and various mechanical properties.

[0011]

EXAMPLES The effects of the polychloroprene rubber composition of the present invention will be described below with reference to examples. Examples 1 to 5 With the compositional composition shown in Table 1, each component was sufficiently kneaded with a Banbury mixer to prepare a polychloroprene rubber composition of the present invention having each compositional composition. The following various tests were carried out using the polychloroprene rubber composition of the present invention having each compounded composition thus obtained.

[Scorch resistance test] JIS-K6300
The Mooney scorch test was conducted in accordance with the regulations. The test is a 125 ° C small rotor (MS125 ° C).
The Mooney scorch time of the unvulcanized polychloroprene rubber composition was measured for 5 point up time (t ₅ ),
The scorch resistance was judged. If the 5-point up time (t ₅ ) is too short, the scorch problem of the rubber composition will occur during storage and extrusion.

[Deformation Rate of Unvulcanized Rubber Composition] The deformation rate of the unvulcanized rubber composition was measured, and the shape retention of the extruded product was determined by the size of the deformation rate. The deformation rate of the unvulcanized rubber composition was determined by the following method. That is, a test piece having a length of 10 mm, a width of 10 mm, and a thickness of 10 mm was cut out from the kneaded material immediately after kneading (that is, an initial thickness of 10 mm). Then 100
A load of g / cm ² was applied at a temperature of 100 ° C. for 10 minutes, and the thickness of the test piece after loading was measured. The deformation rate was calculated from the following equation using the obtained measured values.

Deformation rate = [(initial thickness-thickness after loading) /
Initial thickness] x 100

If the value of the deformation ratio exceeds 30%, the molded product may be deformed or drooped during extrusion.

[Tensile Strength and Elongation] Each rubber composition is heated for 20 minutes to be vulcanized, and the molding temperature is 150 ° C. and the pressure is 15
A sheet having a thickness of 2 mm was produced under the condition of 0 kg / cm ² . From this sheet, a No. 3 dumbbell piece was cut out in accordance with JIS-K6301 and the tensile strength and elongation were measured. [Electrical insulation] From each rubber composition, JIS-K6911
The volume resistivity was measured for the test piece obtained in accordance with the regulations.

[Abrasion resistance of electric wire] Each of the polychloroprene rubber compositions was extrusion-coated so as to have a coating thickness of 3 mm around a copper conductor having a cross-sectional area of 5.5 mm ^2.
Polychloroprene rubber insulated wire was prepared by heating at 20 ° C. for 20 minutes and vulcanizing. A test piece with a length of 30 cm was cut out from each of the polychloroprene rubber insulated wires thus prepared, and each test piece was worn by a grinding wheel wear tester specified in JIS-C3005 after 400 r.p.m. cc) was measured. The various test results obtained above are also shown in Table 1.

[0018]

[Table 1]

Comparative Examples 1 to 7 Each component was sufficiently kneaded with a Banbury mixer in the composition shown in Table 2 to prepare a polychloroprene rubber composition of a comparative example having each composition. Using the polychloroprene rubber composition of Comparative Example having each composition thus obtained, various tests were conducted in the same manner as in the examples of the present invention.
The various test results obtained above are also shown in Table 2.

[0020]

[Table 2]

As is clear from the comparison between Tables 1 and 2, the polychloroprene rubber composition of the present invention has a scorch resistance, a deformation ratio of an unvulcanized rubber composition molded article, and a vulcanized rubber composition. In terms of various properties such as tensile strength, elongation, and electrical insulation of the molded product, the molded product is superior to all the values of the polychloroprene rubber composition of Comparative Example. The electric resistance of the electric wire / cable manufactured using the polychloroprene rubber composition of the present invention is about 2 / about the wear amount of the electric wire / cable manufactured using the polychloroprene rubber composition of the comparative example. The wear amount is 3 or less, and the wear resistance is extremely excellent. The points marked with * in Table 2 are the points where the composition differs from the rubber composition of the present invention and the points where the properties are inferior.

[0022]

The polychloroprene rubber composition of the present invention has good extrusion moldability, good scorch resistance, and excellent electrical insulation and mechanical strength. And, the electric wire / cable of the present invention produced by using the polychloroprene rubber composition of the present invention as an insulating material or a sheath material has excellent electrical characteristics and excellent oil resistance in addition to the original excellent oil resistance and chemical resistance. It has mechanical strength and its practical value is extremely large.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a cabtire cable.

FIG. 2 is a cross-sectional view of a jacket-type electric cable.

FIG. 3 is a cross-sectional view of an insulated wire.

[Explanation of Codes] 1 ... Electrical conductor 2 ... Electrical insulator layer 3 ... Insulated wire core 4 ... Cable wire core 5 ... Inclusion 6 ...・ Sheath layer

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Claims (2)

[Claims] 1. To 100 parts by weight of polychloroprene rubber,
5 to 50 parts by weight of fine powder of silicone resin having an average particle size of 0.5 μm to 100 μm and 10 to 50 parts by weight of carbon black having an average particle size of 85 nm or less are mixed, and a desired amount of a vulcanizing agent is added thereto. A polychloroprene rubber composition characterized by being blended. 2. A wire / cable in which the vulcanized product of the polychloroprene rubber composition according to claim 1 is coated on an electric conductor directly or via another coating material layer.